WO 97/23485 discloses powders for inhalation comprising carrier particles and an additive material for the promotion of the dispersal of the active particles from the carrier particles. The use of gentle milling of carrier particles of diameter 90 to 125 μm in order to remove surface asperities which are suggested to be sites of high surface energy at which active particles can be bound so tightly to the carrier particles that they are not released upon actuation of the inhaler is also disclosed. In some cases the carrier particles are gently milled in the presence of the additive material. However, in all cases, the milling treatment is a gentle one such that the size of the carrier particles is not substantially changed.